Energy Availability Amongst Elite Rugby Union Players During Pre-Season Training

Abstract

In elite rugby union the pre-season training period is used to optimise players’ strength, power, endurance and body composition. Given the increased training loads during this time, players could find themselves at risk of Low Energy Availability (LEA). A state of LEA can be caused by large energy expenditure in exercise (EEE) and/or low energy intake (EI), which reduces the amount of energy available for physiological functions. Despite the majority of the literature focusing on female athletes, it is possible that male athletes are also at risk of LEA, particularly during periods of increased training load such as pre-season. PURPOSE: The purpose of this study was to examine the energy intake, energy expenditure and energy availability of elite male rugby union players during pre-season training. METHODS: During this observational study, three-day diet records were collected for 23 Super Rugby players using video, photographs, checklists and recalls. Energy expenditure data was also collected via heart rate monitoring, GPS tracking and Activity Logs. Skinfold thicknesses (International Society for the Advancement of Kinanthropometry protocols) were used to assess body composition. Data was analysed based on groups established by training goals determined by the teams support staff: weight gain (n=8)/weight maintenance (n=8)/weight loss (n=7). One-way ANOVA was used to identify differences between groups, with post-hoc pairwise comparison of means, adjusted using Bonferroni. RESULTS: For all participants exercise energy expenditure was 2,240 ± 1,140 kcal (mean ± SD). The average energy intake was 3799 ± 958 kcal.day-1 for all participants. The weight loss group had significantly lower mean (± SD) energy availability (6.7 ± 6.4 kcal.kgFFM-1.day-1) than the weight maintenance (20.3 ± 7.6 kcal.kgFFM-1.day-1, p=0.003) and weight gain (28.6 ± 8.0 kcal.kgFFM-1.day-1, p < 0.001) groups. CONCLUSION: This research shows that NZ Super rugby players can, and do suffer from short-term LEA during the intense pre-season training period. However, as this study was observational, the results are only indicative of the three-day sampling period. Therefore, the duration of LEA cannot be determined from this study nor can any health or performance implications. Supported by the University of Otago Research Grant